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Universal Serial Bus Interface – On-The-Go Module
21-72
Freescale Semiconductor
21.5.4
Servicing Interrupts
The interrupt service routine must understand there are high frequency, low frequency, and error
operations to order accordingly.
21.5.4.1
High Frequency Interrupts
In particular, high frequency interrupts must be managed in the order below. The most important of these
is listed first because the DCD must acknowledge a setup buffer in the timeliest manner possible.
21.5.4.1.1
Low Frequency Interrupts
The low frequency events include the following interrupts. These interrupts can be managed in any order
because they do not occur often in comparison to the high-frequency interrupts.
Table 21-57. Error Descriptions
Overflow
Number of bytes received exceeded max. packet size or total buffer length.
Note: This error also sets the halt bit in the dQH, and if there are dTDs remaining in the
linked list for the endpoint, those are not executed.
ISO Packet Error
CRC error on received ISO packet. Contents not guaranteed correct.
ISO Fulfillment Error
Host failed to complete the number of packets defined in the dQH mult field within the given
(micro)frame. For scheduled data delivery, DCD may need to readjust the data queue
because a fulfillment error causes the device controller to cease data transfers on the pipe
for one (micro)frame. During the dead (micro)frame, the device controller reports error on
the pipe and primes for the following frame.
Table 21-58. Interrupt Managing Order
Execution
Order
Interrupt
Action
1a
USB Interrupt
1
EPSETUPSR
1
It is likely multiple interrupts stack up on any call to the interrupt service routine and during interrupt service routine.
Copy contents of setup buffer and acknowledge setup packet (as indicated
in
Section 21.5.3.5, “Managing Queue Heads”
). Process setup packet
according to USB specification chapter 9 or application specific protocol.
1b
USB Interrupt
EPCOMPLETE
Manage completion of dTD as indicated in
2
SOF Interrupt
Action as deemed necessary by application. This interrupt may not have a
use in all applications.
Table 21-59. Low Frequency Interrupt Events
Interrupt
Action
Port Change
Change software state information.
Sleep Enable (Suspend)
Change software state information. Low power managing as
necessary.
Reset Received
Change software state information. Abort pending transfers.
MCF5329 Reference Manual, Rev 3
Summary of Contents for MCF5329
Page 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Page 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...